Examples of electronic components that require hermetic sealing include crystal application products such as crystal resonators and semiconductor elements such as flash memory. A metal thin-film electrode is formed on a front surface of each of these various electronic components, and the electronic components are mounted on a housing such as an electronic component storage substrate and hermetically sealed to protect the metal thin-film electrode from the outside air.
FIGS. 16A and 16B are exploded perspective views of a conventional electronic component housing package. FIG. 16B illustrates a cross-sectional view taken along line X-X in FIG. 16A. FIG. 17A is a perspective view that schematically illustrates a conventional electronic component storage substrate. FIG. 17B is a plan view of the electronic component storage substrate illustrated in FIG. 17A as seen from the position of the line Y-Y in FIG. 17A. An electronic component storage substrate 101 for mounting an electronic component 100 such as a crystal application product includes: a substrate 105 having a mounting surface 103 for the electronic component 100 on its main surface, as well as a rectangular frame-shaped substrate bank section 109 having four corner portions 107 provided on the substrate 105. Additionally, a metal layer 111 may be formed on the front surface of the substrate bank section 109. Further, a lid 113 may be bonded to a top surface of the metal layer 111 via a bonding material 112. In such a configuration, a bonding method such as seam welding, for instance, may be used to join the lid 113 and the metal layer 111 (see, for example, Patent Document 1).
In recent years, electronic devices such as mobile phones and IC cards are growing in prevalence. In addition to improved performance, electronic devices are required to become increasingly smaller and thinner. Accordingly, electronic components 100 and the electronic component storage substrates 101 on which they are stored are also required to become even smaller in size.